Encapsulation is widely used in the pharmaceutical and nutritional industries. In these industries, encapsulation is primarily used for taste masking and as a buffering agent. In general, encapsulation is used to protect an inner core made from one substance (usually an active or a desired substance) with an outer shell made from a different substance (usually an excipient or filler). The core material would normally be subject to the degradation effects of acid (e.g., in the stomach), oxygen, heat, moisture, etc. However, while encapsulated, the degradation of the core material is greatly reduced if not completely prevented. This greatly increases the shelf-life of the core material.
A common technique for encapsulating medicines is spray drying. Spray drying is relatively inexpensive and produces a finely divided product that is readily used in the preparation of finished pharmaceutical agents. However, spray drying is very limited in its applications and is usually utilized with relatively large core materials.
In view of their relatively long shelf life, high durability, and relatively low cost, tablets are a favorite means of delivering a medicine or nutritional supplement.
Normally, there is only one machine that can make a tablet, namely a tablet punch. If the medicine or nutritional supplement is not directly compressible, it must be made so by using wet granulattion or dry granulation. Medicinal tablets are usually formed by direct compression of an active ingredient. However, if the active ingredient is not compressible, other ingredients (e.g., excipients or fillers) may be used or other techniques must be employed to form a solid dosage form. Unfortunately, each of the aforementioned methods has its drawbacks.
In direct compression, a powdered pharmaceutical is mixed with water and the mixture is compressed to form a tablet. Wet and dry granulation use powdered excipients in their formulations to make tablets. Unfortunately, when encapsulated pharmaceuticals (having dimensions on the order of the powder) are utilized, a relatively high percentage of the microcapsules are destroyed or defaced by the high pressure applied to same or by abrasive components present in the excipient.
Similar problems are encountered when microcapsules are incorporated in a compressed powder matrix (including animal feed pellets, compressed vitamin and mineral formulations) and pharmaceutical tablets (i.e., pills) for both human and veterinary applications.
It is desirable to have a method of encapsulation that can withstand the pressure of manufacturing tablets and reduce the amount of waste created by tablet manufacturing process. Also, it is desirable to have a tablet that can release medicine in a more controlled process and with more precise timing.